Plunger mechanism for blindstitch sewing machines



June 4, 1929. C, w, MUELLER 1,715,562

PLUNGER MEGHANISM FOR BLINDSTITCH SEWING MACHINES Filed April 26, 1927 5Sheets-'Sheet l WITNESS: l

3N/m ATTORNEY.

June 4, 192,9. c. w. MUELLER 1,715,562

'l PLUNGER MECHANISM FOR BLINDSTITCH SEWING MACHINES Filed April 26,1927* 3 Sheets-Sheet 2 Q l im l.

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D NVENTOR.

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A TTORNEY.

June 4, 1929.

c.-w. MUELLER PLUNGER MECHANISM FOR BLINDSTITCH SEWING MACHINES :ssheets-sheet 5 Filed April 26, 1927 Patented June 4, 1929.

UNITED CHARLES W. MUELLER, F ST. LOUIS, MISSOURI, ASSIGNOR TO LEWISINVISIBLE STITCH MACHINE COMPANY, 0F ST. LOUIS, MISSOURI, A CORPORATIONOF MAINE.

PLUNGER MECHANISM FOR BLINDSTITCH SEWING MACHINES.

Application led April 26, 1927. Serial No. 186,672.

This invention relates to new and useful improvements inplungerbperating mechanisms for blind stitch sewing machines generally,although the invention is particularly adapted for use in connectionlwith a blind stitch sewing machine for felling coat linings, as isshown and described in my copending application Serial No. 186,674,tiled on the 26th day of April, 1927. o

In felling operations generally, it is desirable to provide a blindstitch sewing machine in which the needle will enter and emerge-from theupper face of the b ase layer during alternate needle reciprocations andfor this purpose a lower plun er is provided for projecting a node ofsaid ase layer into needle penetrating position immediately prior toalternate needle penetrating strokes.

One of the principal objects of my invention is to provide a plungermechanism for the purpose set forth in which differential reciprocatorystrokes will be imparted to 'the plunger whereby on one stroke of theplunger the base layer will not be engaged by said plunger and on thenext stroke of the plunger the base layer will be elevated so as to forma node therein for the entrance by the needle.

Another object of the invention is to provide a plunger mechanism whichincludes a rock shaft, a rotary driving shaft, and toggle connectionsbetween said shafts whereby differential ieciprocatory strokes will beimparted to the plunger.

Another object of the invention is to p iovide a plunger operatingmechanism which is extremely simple in construction and which ispositive in its action.

With these and other objects in view which will more fully appear, thenature of the invention will be more clearly understood by following thedescription, the appended claims, and the several views illustrated inthe accompanying drawings.

- In the accompanying drawings which illustrate one form of myinvent'mn:

Figure 1 is a rear elevation of a blind stitch sewing machine equippedwith a plunger mechanism embodying my invention, I

Figure 2 is a bottom plan View, parts thereof being shown in section tobetter disclose the plunger mechanism, A

Figure 3 is a sectional View taken at right angles to Figure 2,

tions of the parts when the plunger is at the lower end of its longstroke, and

Figure 6 is a series of diagrammatic illustrations showing the relationbetween 'the plunger and the base layer during a complete cycle ofoperations.

-Like reference `.numerals designate corresponding parts throughout theseveral figures of the drawings.

Referring to the accompanying drawings, I have illustrated a blindstitch sewing machine of the well known Lewis type and this machine isillustrated in my'co-pending application Serial No. 186,674, filed onthe 26th day of April, 1927.

This machine includes a base 5, a work supporting arm 6, a standard 7,an overhanging arm 8, and a stitching head 9 supported by theoverhanging arm directly above the outer end of the work arm 6. Theneedle mechanism is not shown in these drawings as it forms no part ofthe present invention, but for the purpose of reference, the needlemechanism associated with this particular machine isshown and describedin my co-pending application Serial No. 180,527, filed on the 2nd day ofApril, 1927.

Fixed to the bottom portion of the stitching head 9 is a presser foot 10and cooperating with this presser foot to feed the material through themachine is'a work presenting mechanism which I have illustrated as awhole by the reference numeral 11. This work presenting mechanismincludes an intermittent feeding mechanism of the 4-motion type andthese four motions are transmitted to the feed dog through the medium ofthe rock shafts 12 and 13 which are journaled in the work arm 6, therockshafts being oscillated by pitmen 14 and 15 respectively which aredriven from the main rotary shaft 16 which is journaled in the upper endof the standard 7 and within the overhanging arm 8. This work presentingmechanism 11 includes aplunger 17 which is slidably mounted in the outerend of the work arm 6A for vertical reciprocations. y The As previouslystated, means are provided.

for vimparting differential reciprocatory strokes to this plunger, or 1nother Words,

f means are provided for imparting short and long reciprocatory strokesto thcplunger. vFor this purpose, I have provided the toggle operatingkmechanism shown in detail in Figures 4and 5. Fixed to the rotary drivinshaft 16 directly above the standard 7 1s an eccentric 20 and a'gearpinion 21, the latter driving a 1 to'2.^gear 22 which is located withinthe standard 7 and journaled on a stub shaft 23 fixed to said standard.Fixed to the outer face of the driven gear 22 is an eccentric pin 24 andjournaled on this pin is a guide 25 in which is slidably mounted a lever26 having its upper end formed with a sleeve27- which .surrounds theeccentric 20. Secured to the plunger rock shaft 18 is a rock arm 28, atthe outer end of which is pivotally connected, as at 29, the lower endof a substantially vertically disposed link 30. The u per end of thelink 30 is pivotally connecte as at 31, to the outer end of an arm 32which is pivoted, as at 33, to the base v5 at a point above the plungerrock shaft 18. A link 34 has its upper end pivotally connected, as at35, with the lower end of the lever 26 and the lower end of the link 34is pivotally con nected, as at 36, with the pivoted arm 32. It will,therefore, be seen that the lever 26 and the link 34 cooperate to form atoggle connection between the rotary driving shaft 16 and the plungerrock shaft 18. It will also be noted that the lever 26 is slidably suportedfor' endwise movement upon a shi table fulcrum, the fulcrumpartaking of a circular path of travel due to the rotation of the gear32.

. When the parts are in the positions shown in full lines in Figure 4,the plunger 17` is located at the upper end o'f. its short stroke anddirectly below the fabric F, as indicated at A in Figure 6. In thisposition the high point of the eccentric 20 .is directly above the shaft16. The shaft 16 rotates in the direction indicated by the arrow, andinasmuch as the gear connection is a' 1 to 2 coupling, it follows thatwhen the high point of the eccentric 20 is moved 180, the eccentric in24 of the gear 22 will be moved downwardly and towards the left for adistance of 90. As the eccentric 20 is thus moved for 180, the lever 26Vslides in the guide25 and consequently the position of the lever 26 isshown in dotted lines in Figure 4. In this position ofthe parts, thepivot 35 has been lowered and-.also been moved towards the left. Thisresults in the plunger rock shaft A18 being oscillated `to move theplunger 17 'downwardly to the lower end of its short stroke as indicatedat B in Figure 6. The eccentric 20 is then turned for 180 andsimultaneouslyv the gear 22 is rotated so as yto move the eccentric pinl \24 upwardly towards the left for a distance of 90, or to the fullline position shown in Figure 5. As a result, the pivot 35 of the toggleconnection is at its highest extreme position towards the left, andconsequently the pivoted arm'32 is'oscillated for a greater distancewith the result that theplunger I rock shaft 18 will be given acorrespondinglyv increased amount of. oscillation, and the plunger 17will be moved tothe upper end so as to move the plunger 17 downwardly tothe lower end lof its long stroke as shown` at D in Figure 6. Thiscompletesvthe cycle 4of operation. When the plunger 17 is at the upperend of its long stroke, the pivot 35 is in the horizontal planeindicated by the line .fr in Figure 5, and when the plunger is at thevupper end of its short stroke, the pivot 35 is inthe horizontal planeindicated by the line y in Figure 4. Thus the distance between thehorizontal lines and y indicate the difference in vertical movements ofthe link 34 when the plunger 17 is at the upper end of its short andlong strokes.

It is of course to be understood that the details of structure andarrangements of parts may be variously changed and modified withoutdeparting from thel spirit and v scope "of my invention.

I claim: I

1. A plunger mechanism for blind stitch sewing machines comprising incombination,

a vertically reciprocatory plunger, meansl for imparting differentialreciprocatory strokes to said plunger including a rock shaft operativelyconnected to the plun er, a rotary driving shaft, and connections etweensaid shafts including a toggle.

2. A plunger mechanism for blind stitch sewing machines comprising invcombination,

a vertically reciprocatory plunger, means for imparting differentialvreciprocator strokes to said plunger including a roc shaft operativelyconnected to the plunger, a rotary drivin shaft, and connectlons betweensaid sha s including a toggle comprising av lengthwise movable leverhaving a shiftable fulcrum, a link connectinglthe lever and' rock shaft,and means for shift ing the fulcrum of the lever.

3. A plunger mechanism for blind stitch.

sewing machines comprising in combina tion, a vertically reciprocatoryplunger, means for imparting differential reciprocatory strokes to saidplunger including a rock shaft operatively connected to the plunger, arotary driving shaft, an eccentric xed to said driving shaft, a leverjournaled on said eccentric, a shiftable ful'crum for the lever havingsliding connection therewith, a rock arm on said rock shaft; a linkconnecting said lever and rock arm, and meansfor continuously shiftinsaid fulcrum.

5. A plunger mec anism for blind stitch sewing machines comprising incombination, a vertically reciprocatory plunger, means for impartingdifferential reclprocatorystrokes to said plunger including a rock shaftoperatively connected to the lunger, a rotary driving shaft, aneccentric xed to said driving shaft, a lever journaled on saideccentric, a gear driven by said rotary shaft, a guide for slidably.engaging the lever eccentrlcally journaled on said gear, andaconnection between the lever and the rock shaft for oscillating thelatter. y

'6. A lunger mechanism for blindA stitch' signature.

sewing machines comprising in combination, a y vertically reciprocatoryplunger, means for imparting differential reciprocato strokes to saidplunger including a rogk shaft operatively connected to the plunger, arotary driving shaft, an eccentric fixed to said driving shaft, a leverjournaled on said eccentric, a gear driven by said rotary shaft, a guidefor slidably engaging the lever eccentrlcally journaled on said gear, arock arm on said rock shaft, and a link connecting said lever and saidrock arm.

7. A plunger mechanism lfor blind stitch sewing machines comprising incombination, a vertlcally reciprocatory plunger, means for impartingdifferential, reciprocatorystrokes to said plunger including a rockshaft operatively connected to the.v plunger, a rotaryv driving shaft,and connections between said shafts includin a toggle ,comprising alengthwise mova le lever having a fulcrum movable about a circularpath,a link connecting the lever and rock shaft, and means for rotatinthe :fulcruxn about its circular path once uring every two revolutionsof the rotar shaft.

'- 8. A p unger mechanism for blind stitch sewing machines comprising incombination, a vertically reciprocatory plunger, lmeans for impartingdifferential reciprocatory strokes to said plunger including a rockshaft operatively connected to the plunger, a rotary driving shaft, anf'eccentric fixed to said driving shaft, a lever journaled on saideccentric, la gear pinion fixed to the rotary shaft, a 1-to-2 geardriven by said.

pinion, a guide for slidabl engaging the lever eccentricallyjournale enlsaid gear, and a connection between the lever and the rock shaft for,oscillatin the latter.

In testimony whereofl CHARLES W. MUELLER.

